In many buildings with agricultural applications, such as greenhouses or animal shelters, it is desirable to provide ventilaton This allows plants and animals to obtain air and is an effective means of moderating the temperature, humidity and other environmental conditions of the interior of the building. However, the ventilation systems can allow pests such as birds, insects, moths and flies to enter the building. The pests may then destroy plants or infest animals housed in the building.
In the past, this problem has been addressed by using a venting system in the roof of the building that includes a hole or aperture in the roof, a flap that may cover the aperture and fabric extending between the aperture and the flap. The fabric allows air to flow into the building but excludes pests. However, this fabric often becomes dirty. This reduces the flow of air through the fabric and the fabric requires cleaning. To clean the fabric requires access to the upper surface of the roof of the building. Access to the fabric is difficult, and climbing on the roof of the building is undesirable, particularly when the building is constructed of material that is easily damaged, as is the case for a plastics or glass greenhouse.
The object of the present invention is to overcome the abovementioned difficulties, or at least provide the public with a useful alternative.